


Full Circle

by murcielag0



Category: Haikyuu!!
Genre: Bottom Miya Atsumu, Brother/Brother Incest, Brother/Sister Incest, Double incest, Foursome, Incest, Miyahina Four, Multi, Natsu/Atsumu/Shouyou centric, Pegging, Polyamory, Sibling Incest, Strap-Ons, Switching, Threesome, first time pegging
Language: English
Status: Completed
Published: 2021-01-18
Updated: 2021-01-18
Packaged: 2021-03-12 19:55:11
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 2,640
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/28765923
Author URL: https://archiveofourown.org/users/murcielag0/pseuds/murcielag0
Summary: Natsu cherishes the not-so-distant memory of her first time with her brother's boyfriend, Atsumu. Now he's her boyfriend too, so it's no surprise for her to choose Atsumu to be another one of her firsts, helped along by her niichan.In which Natsu and Atsumu come full circle, Shouyou is a proud big brother, and Osamu is in for a bit of a surprise when he learns what they've been up to without him.
Relationships: Hinata Natsu/Hinata Shouyou/Miya Atsumu/Miya Osamu
Comments: 8
Kudos: 27





	Full Circle

**Author's Note:**

> Hi! Please read the tags carefully - if the content makes you uncomfortable, please scroll no further and sashay away. ♥
> 
> Miyahina four (Natsu, Shouyou, Atsumu, Osamu) is a polyamorous foursome that enjoys being together in many different combinations. This fic is Natsu/Shouyou/Atsumu centric, but Osamu is brougt into the mix later on, much to his surprise and everyone's delight.
> 
> Enjoy!

### Full Circle

When Sho and Natsu come back from their shopping trip with twin devil-smiles on their faces, Tsum knows he's in for it.

Tsum watches Sho hand the black bag from a favorite adult store over to Natsu, who giggles and skips into the bedroom. He groans, stomach clenching with the dreaded combo of fear and excitement that is the calling card for the Hinata siblings.

"Don't look so worried," Sho says, climbing into Tsum's lap on the couch.

"Yeah right," Tsum says, licking the smirk off of Sho's face before Sho tips his head back, looking deeply into his eyes before he bends down and tongue-fucks his mouth, kissing him hard and deep and breathless in a matter of seconds. 

"Ahem!" Natsu says a few minutes later, catching them mid-makeout. Tsum looks over Sho's shoulder and his jaw drops.

"Fuck!" he exclaims, wild eyes darting all over Natsu's outfit—if this even qualified. Her tiny breasts are framed snug in a black, open cup bra that's more straps than cloth, which matched, more or less, the strap-on harness hugging her hips... the harness with the big, black dildo jutting from it, 9 inches of gleaming silicone in a girth that has his mouth running dry.

"Yep! That's the idea!" Natsu grins, sauntering over to the couch as much as a girl of 16 can saunter. She casually puts one foot on the edge of the couch, showing off her black stiletto pumps. She tosses two black objects to Tsum, who catches them, frowning—what the? Kneepads?

Sho giggles. "I think you better put those on, Tsum," he says, nibbling Tsum's cheek.

Tsum looks from Sho, to Natsu, and feels his face go red hot. Sho and Natsu lead him into the bedroom, and he groans the entire way, that combo of dread, fear, and excitement making him uncomfortably hard. At the bed, Natsu unceremoniously pulls down his pants, then sits him down so he can put on his kneepads. Tsum looks at Sho for reassurance, but is met with mischievous delight and fingers tweaking his nipples through his tanktop.

Then Sho turns to Natsu. "You're good with getting him prepped?"

Natsu rolls her eyes. "Of course, niichan. I've done it for you lots of times now."

Sho leans over and kisses her, gentle and hot and sweet, but when they pull away to look at Tsum, there's nothing but hunger on their faces.

"Lay back, Tsumu-nii," Natsu orders, and Tsum rushes to comply, propping his head in the pillows.

Sho climbs up next to him, and Natsu positions herself between his legs. Sho chuckles, and pulls the pillow out from under his head, and passes it to Natsu, who smacks him on the thigh so he'll raise his hips. Tsum whines, but lets her put the pillow under him so his ass and balls and everything else is on display.

"What's the matter?" Sho asks taking off his clothes and kneeling naked beside Tsum.

"Are ya... mad at me or somethin'?" Tsum gives both of them a worried glance.

Sho grins wider, and Natsu lets out her cute, girlish laugh. "Awww, why would you think that, Tsumu-nii?"

Sho strokes a hand through Tsum's hair. "Maybe you sprung this on him too quickly," he says to his sister.

She pouts, but climbs carefully over Tsum's lap to straddle his waist. "But I wouldn't do this if I was mad," she says, bending down to kiss him. Tsum moans in pleasure, big hands encircling her waist, gripping her tight. Sho whistles, enjoying the view. He reaches over to the nightstand and pulls out the lube, and a couple of Tsum's toys that might be useful.

Natsu looks so cute and tiny astride Tsum, Sho feels his dick hardening at the luscious sight. He's glad he had a chance to eat her out in the backseat of the car before they came in with their purchases. He palms her bare backside framed by the harness straps, and traces down between her legs, then dips his fingers inside the edge of the strap to feel where the built-in dildo is held tight inside her cute puss, already dripping wet in anticipation. He pushes it deeper inside her and she moans, kissing Atsumu harder, and then Shouyou withdraws his fingers and gives her a playful swat on her rump that leaves a faint imprint. Natsu jerks and whines at the sting, then she giggles, and pulls away from Tsum, saliva strings connecting their lips.

"Hey, aren't you going to fuck him?"

"Yep!" she agrees, resuming her position between Tsum's legs. Sho hands her the lube and the two dildos from the drawer, a couple of sizes smaller so she can work up to her strap-on.

"Thanks, niichan!"

Sho winks at her. He reaches for Tsum's rock hard dick, and strokes it a few times. Tsum grunts, writhing. 

"So what—ah!—brought this on—ahhh!—exactly?" Tsum asks, breathy with desire.

Natsu makes a show of lubing her fingers before tapping them on his entrance. Tsum shivers, and Natsu starts working two fingers inside him at once, partly since her hands are so slim, and partly because she knows Osamu fucked him for a long time that morning before going to the restaurant, so he's already supple and willing under her touch.

"Well you were my first, Tsumu-nii," Natsu explains, "And so I thought, why not be my first this way, too."

She grins, and Sho grins, and Tsum closes his eyes, laughing in surrender.

"Alrighty," he says. "Baby's got her first strap-on, so let's get her a notch on that belt."

Sho laughs, and straddles Atsumu's ribs. "I knew you'd get it!" he says, palming Tsum's pecs.

"I'll do my best!" Natsu says, slipping in two more fingers. Tsum moans, fisting the bedding as she twists her wrist.

"Nacchan, I can have his mouth right?" Sho quirks his head back to look at her.

"Sure! This shouldn't take me too long."

Sho traces Tsum's lip with his thumb. "Thanks!"

Tsum's belly clenches with growing need, and he lowers his jaw in invitation, already salivating. Sho scoots up and gets into position, guiding his cock into Tsum's waiting mouth. Tsum holds on to Sho's perfect butt cheeks, Sho's hands fisting his hair as he slowly fucks into Tsum's throat, carefully picking up the pace as Natsu works him open with tiny hands, and then his toys, finding the angles that make him cry out, muffled as it is by the dick down his throat.

Sho rocks his hips more forcefully and Tsum groans, saliva trailing down the corners of his mouth as he eagerly sucks Sho as far back as he can go. Natsu hits a particularly good spot inside Tsum's ass, making him buck involuntarily, tears gathering in his eyelashes.

"Don't make him cum," Sho warns, Tsum's fingers digging into his flesh.

"I _know_ , niichan," Natsu huffs, then rails the larger dildo all the way to the base. Tsum arches, and Sho groans.

"Coming," he whispers, and then jerks, spilling hot spurts of cum all over Tsum's tongue and the back of his throat. Tsum swallows frantically, his dick jumping between his legs and begging to be touched.

"I think he liked that," Natsu reports, watching Tsum's reactions avidly.

"Course he did." Sho licks his lips and sits back, freeing Tsum's mouth so he can catch his breath.

Tsum feels blissful, half out of it from being used so well by his two favorite gingers.

"Hey, don't fade," Sho laughs, caressing Tsum's face and moving to lie down beside him. "How's he doing?" he asks Natsu, who pulls the dildo free with a squelch.

"He's ready," she says, licking her lips.

Sho brushes Tsum's sweaty hair from his face. "Time to turn over, babe." 

Tsum rolls slowly to his stomach, his hole stretched and dripping with lube, twitching and needy—he can't believe sweet little Nacchan is seeing him this way, up close and so personal, and his skin burns with a sense of shy intimacy that does nothing to relieve how hard he is. Sho sits against the headboard, and guides Tsum over to his lap where Tsum gratefully rests his blushing cheek on Sho's thigh.

"Up!" Natsu commands, rubbing the backs of Tsum's thighs as he gets to his knees. 

He's grateful now for the knee pads, and when he hears the lube cap he trembles, both wanting to be fucked and also kinda scared of _Nacchan_ being the one to dick him down. It's so hot and so surreal he's not sure of anything but wanting to cum, and wanting Nacchan to be the one to wring all the pleasure out of him. She squirts more lube on his asshole and pushes the glob in with her fingers.

"C'mon," Tsum pleads.

"Remember to go slow," Sho says to his sister, who sticks out her tongue.

"Only if I want to," she retorts, grinning like an imp.

Sho chuckles and cards his hand through Tsum's hair, eyeing her. "Remember how sweet and loving he was with you, Nacchan? Making sure you felt really, really good when his big cock went inside you for the very first time?" Sho points out.

"Yeah. That's why I love Tsumu-nii so much. And I was only kidding, I want it to be good for him," she answers, caressing Tsum's ass cheeks in reverence, and petting his thighs and his back in gentle circles, offering reassurance the way she's used to receiving it when they're all in bed together.

"Relax," she reminds him. Then she lines up her strap-on, and begins to push. Tsum's breath leaves him all in a rush, that thick dildo breaching him and slowly easing inside, inch by inch. Nacchan holds him steady, spreading his ass cheeks and pausing every so often, until she's bottomed out.

"Nice, real nice Tsum," Sho says.

Tsum nuzzles Sho's lap and then hangs on to his waist as Natsu starts pulling out. Tsum whines, the dildo dragging along his walls and shocking him with how good it feels. He distantly hears Sho talking to Natsu, guiding her in what to do, and whatever he says, it works—Tsum starts shaking from the intensity of it all, dick swaying between his legs, so aroused he's slipping into some other state of being. Sho turns his head, caresses his face and nudges his mouth open so his hardened cock can slip back between his lips. Tsum salivates, sucking and licking it while Natsu starts to thrust more seriously, driving that black dildo so deep he can see galaxies.

His awareness is on them and them alone—Sho's cock dipping into the tightness of his throat, and Natsu fucking him, ramming him with that big strap-on so good it's like she was born with it. He's panting, trying to breathe with tears welling in his eyes from the slams against his prostate, knees driven harder and harder into the bed from Natsu's deceptively strong thrusts. She gets into a rhythm and then adjusts until she has him singing with desire, near-choking on Sho's cock from delerium.

Sho fists his hair, groaning and shouting a warning before his balls empty for the second time. Tsum takes it all, swallows everything but the last spurt which lands on his lips and cheek, Sho quivering with pleasure under him.

"Nacchan," Sho says, and it must be some signal because Natsu gets up on one knee and then pistons her little hips so she's exactly aligned with his prostate, stroking it over and over and shocking him into a blinding, furious orgasm that pulls a scream out of his throat. It goes on a long time—she's relentless and Sho is praising them both but Tsum can't totally understand the words, between the wild squirts of hsi cum going everywhere and the tears running over his cheeks.

Tsum goes limp on the bed, twitching with the aftershocks until Natsu finally pulls out, sitting back on her heels, and wiping the sweat from her forehead.

"Beautiful," says Sho, wiping the cum from Tsum's face and licking it into his mouth. "Both of you," he adds, reaching for Natsu who comes over to lie next to him, head cradled on his other thigh. Then Natsu leans over and peppers kisses all over Tsum's face, wiping the tears from his cheek and exchanging a long, sensual kiss.

"Did you cum too?" Sho asks Natsu, fingers tracing lazily down her shoulder while she and Tsum make out a little.

When she pulls away, she shrugs. "I was close... but I guess I was too focused? Making sure I was doing everything right."

Tsum frowns, and Sho angles his hand to circle her small breast, caressing over her nipple. 

"I think we can help out with that," Sho smirks, meeting Tsum's gaze.

"You bet," Tsum agrees, beckoning her closer. 

She winds up on her back in Sho's lap, Tsum grasping her leg and curving it over his body, kissing her sweetly. Sho weaves his fingertips into her thick red hair, massaging down her head to her neck and shoulders, and then moving to her tits. He flicks and teases her nipples in steady circles, while Tsum slips his talented fingers underneath the front of the harness to do the same to her clit.

She's had a dildo inside her for a while now, so it doesn't take her long to start breathing hard, her hips jerking back and forth involuntarily as her niichan and her Tsumu-nii arouse her right to the edge, and then keep her there, trembling and whining against them until finally letting her cum, shaking and burying her face in Tsum's neck. She whimpers, and Tsum kisses her gently, before starting right up again on her clit, making her cum again almost instantly from being at such a heightened state of arousal for quite some time. They hold her as she comes down from the high, twitching and groaning, and then going limp, a satisfied smile on her face.

For a while none of them move, just blissed and sated in a tangle on the bed. Tsum grins up at Natsu, rolling his upper body enough to pull her in for a more serious kiss. Sho leans back in the pillows, satisfied to watch them fool around until they can find the energy to go get in the shower.

"Thanks, Tsumu-nii!" Natsu says, giving him an exaggerated _smoooooooch_. Tsum laughs, tucking her into his chest.

"My pleasure, Nacchan," he replies. "And thank _you_."

She giggles, and then they reach for Sho who kisses them both, all of them laughing and happily entwined on the bed.

And that's exactly how Samu finds them when he comes home early from work—Tsum's gaping ass, Natsu's strap-on the obvious culprit, and Sho's smug little smile, the clear instigator behind everything that went down while Samu was at work.

Samu orders them all into the shower, and when they're nice and clean, he turns each Hinata sibling over his knee. He play-spanks the both of them—sixteen smacks for Natsu, twenty-three for Sho—for not waiting until he could be there to watch Tsum's first time being pegged, and Natsu's first pegging. 

Sho and Natsu apologize by giving both twins blowjobs, though they enjoy this too much for it to be considered any kind of punishment. So Samu and Tsum team up to fuck them silly, Samu with Natsu, and Tsum with Sho, both pairs side by side on the bed as the Miyas put the Hinatas facedown on the bedding, hips up in the air, and then rail them from behind.

Sho and Natsu twine their fingers in the space between them, wearing matching devil-smirks as they're pounded into orgasm after sweet orgasm, very pleased with themselves indeed.

**Author's Note:**

> This was a twitter thread originally, now refined and posted here for easier readability. Thanks for reading! <333


End file.
